Richest collection of animals of the Ordovician period was found in the Chinese province of Hunan
(ORDO NEWS) — The early Ordovician was a time when the animal world experienced an unprecedented explosion of biodiversity. And now, in the south of China, they found a burial place of impeccably preserved fossils of that period.
Now scientists will be able to better understand exactly how the global change in faunal composition took place, which turned the primitive ecosystems of the Cambrian period into more progressive Middle Paleozoic ones.
Lagerstätts are a real “promised land” for paleontologists: these unique mass graves of fossils, formed under special conditions, preserve not only hard (shells, bones, etc.), but also soft parts of the body, which allows you to see the ancient animal as it was in the last moments of your life.
There are several dozen such places around the world, whose age ranges from one thousand to one billion years.
The distribution of lagerstetts over time intervals of geological history is uneven: for example, only three such deposits are known from the Permian period , and more than a dozen from the Cambrian.
That is why it is especially valuable to discover not just a lagerstette, but one that belongs to a little-studied period of earth’s history. And Chinese scientists were lucky to make such a discovery.
A fossil burial dating to the early Ordovician period , about 475 million years ago, has been found in Hunan province in southeast China. The new fauna, called the “Lesya fauna”, occupies a hitherto unexplored time interval of the Ordovician period.
In addition, it formed in tropical latitudes, while all other known Ordovician lagerstettes formed in the polar regions of the planet.
In total, the new fauna includes 11 types of animals, and most of the fossils are preserved just perfectly. For example, in trilobites , the digestive tract is clearly distinguishable, and in sponges and echinoderms, the smallest details of the internal skeleton.
Based on species diversity, early Ordovician marine ecosystems were already quite complex and included burrowing, sessile, crawling, swimming, and planktonic taxa.
The discovery confirms that the early Ordovician was a time of great biological change, when the primitive fauna of the early Paleozoic was replaced by more progressive ones, which were characterized by reef-building organisms that feed on the filtration of sea water.
Unfortunately, most of the amazing animals of the Ordovician period did not survive the mass extinction at its end, but their extinction cleared the way for the first fish, and in the distant future, for terrestrial vertebrates.
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